How does it work?

PXE Boot process

In case of PXE booting, the client looks for DHCP server, the DHCP server provides the network configuration and hands over further booting to TFTP server. The client then fetches "linux-ltsp" - kernel and "initrd-ltsp" - initial ram disk. Once the booting of the kernel and initrd completes, booting into the chroot image begins. Upon booting, the clients runs /etc/init.d/ltsp-client.init

LTSP init scripts

ltsp-client.init is responsible for launching ldm (ltsp display manager) and fetching various variables from /etc/lts.conf, it also launches mounter script that mounts local devices into the user's session on the server. Various services required by the client such as sound using PulseAudio, local devices using cdpinger and ltspfsd, printing using jetpipe are also set up by the ltsp-client.init.

LTSP Display Manager

LDM supports login to the server via ssh. LDM logs in user and starts Xsession over ssh, it also supports authentication via ssh and Xsession without encryption(LDM_DIRECTX).